Automate Table Relations in Data Connector - Revisited

[andyphenix]

Revisiting #97

From what I can tell (and similar to the most recent comments on #97) the behavior demonstrated in the Relationships sample only works under certain conditions. That is, Power BI Desktop appears to infer the relationship between the two tables only if the following is true:

• the join columns on each side of the relationship have exactly the same name
• there are no other columns on each side of the relationship that have the same names

Furthermore, the table join itself appears to be superfluous.

This doesn't appear to be the case in Power BI desktop itself i.e. it will happily infer relationships (albeit not always correctly) without both of the above conditions being true.

Can someone clarify whether this is a limitation of the SDK and if so, will it be addressed in an upcoming update. At the minute, we find we have to uniquefy all of our column names across tables (we're using the table name prefix), and rename join columns accordingly. It's also unclear whether the Table.NestedJoin capability changes the behavior of the data connector in Power BI desktop.

[1] https://github.com/Microsoft/DataConnectors/tree/master/samples/Relationships